Canalplan Forums

Discussions => Canalplan Site issues => Topic started by: IanMac on Jul 24, 2019, 12:51 PM

Title: Three Mills Lock.
Post by: IanMac on Jul 24, 2019, 12:51 PM
I now understand having been there, why it did not make sense in Canal Planner. It is shown the wrong way round, the uphill side of the lock is Three Mill Prescott junction end.
I was also attempting to add that one can just turn a 71ft boat above the lock and weir with low flow, by shafting the boat round, it is very tight. Not sure if you could get a 72ft boat round. I now think this should be a separate feature.
So how does one correct this?
--
Cheers Ian Mac
Title: Three Mills Lock.
Post by: Shultzy on Jul 24, 2019, 07:59 PM
If you look at street view and picture 11 it looks as if it is correct. Could it be that this is a tidal lock which then depends on the time of day?
Create a new place and then add the length restriction.
Title: Three Mills Lock.
Post by: Stephen Atty on Jul 24, 2019, 10:02 PM
Three Mills would seem to be a tidal lock if you look at the waterways round it.
Title: Three Mills Lock.
Post by: IanMac on Jul 25, 2019, 09:08 AM
Three Mills is a Tidal Lock, It takes the level from upper Three Mills Wall River via the Prescott Channel down the lock to the tideway via Prescott Tidal Pound. There is a weir along side the lock and the water was definitely going over the weir and downhill.  It should have the same notation as Bow Locks No. 20 which also lifts the tidal river up to the River Lee.
Confusion may occur as both the River Lee and the Bow Back waters are semi tidal. The Bow Backs are lower than the River Lee and entered by either City Mills or Carpenters Locks, Both of which also act as Flood defences except for High Spring Tides, which I think the Thames Barrage now stops.
Title: Three Mills Lock.
Post by: Shultzy on Jul 25, 2019, 10:47 AM
Maybe we should have a new symbol (arrows in both directions) to denote a tidal lock?
Title: Three Mills Lock.
Post by: Aegidian on Jul 25, 2019, 12:55 PM
Quote from: ShultzyMaybe we should have a new symbol (arrows in both directions) to denote a tidal lock?

i think that would be very sensible <>> or <<> depending on the position of the tidal waters (the double gates pointing in different directions indicating the tidal side, or rather the side with variable levels.)

Three Mills is COMPLEX, not only does the lock and sluice hold the tide back, but the sluices are also used for flood control on the Lea above, and withhold different levels of water at different times. Let me show you around it sometime.
Title: Three Mills Lock.
Post by: Shultzy on Jul 25, 2019, 04:38 PM
I will take you up on the tour when I'm in the vicinity. I think the \"<>> or <<>\" is a good idea. In this instance is the lock symbol pointing in the right direction.
Title: Three Mills Lock.
Post by: IanMac on Jul 25, 2019, 10:51 PM
The >> should be pointing towards the Prescott Tidal Pound. The next question is given that the Bow Back waters are semi tidal should Capenters Rd and City Mills Locks be <>> as well.
The same will question apply to Brentford Gauging lock. and Richmond Lock & Teddington locks on Thames.
Not sure were else is semi tidal.

(https://i.postimg.cc/3d08GsFq/DSC-6652.jpg) (https://postimg.cc/3d08GsFq)

(https://i.postimg.cc/ns2pZpnX/DSC-6653.jpg) (https://postimg.cc/ns2pZpnX)

(https://i.postimg.cc/wtggS7YK/DSC-6654.jpg) (https://postimg.cc/wtggS7YK)
Title: Three Mills Lock.
Post by: Stephen Atty on Jul 26, 2019, 09:51 PM
You can try raising it as a feature request in the bug tracker
Title: Three Mills Lock.
Post by: Shultzy on Jul 26, 2019, 11:59 PM
Feature request in the bug tracker added